"We ... focused on clarity as well as utility," said Craig Federighi, senior vice president of software engineering, told developers.

Federighi trumpted new typography, icons, tool bars and dock in Yosemite as well as a "gorgeous" trash can for the Mac desktop.

Many updates in OSX 10, which will be available for free to consumers in the fall, are focused on making it easier to share information among Apple devices with new continuity tools. Handoff recognizes nearby iPads, iPhones and Macs and allows you to send documents to them with a swipe.

Macs will also be able to pick up calls from nearby iPhones and function as a speaker phone. Mac desktops will also be able to dial a nearby iPhone, which Federighi demonstrated by placing a call to Dr. Dre.

"What time should I show up for work?" Dr. Dre asked, referring to Apple's recent acquisition of Beats headphones last week.

The company said the operating system includes a "dark mode" for less jarring transitions between apps and the operating system.

OSX Yosemite also expands the functionality and updates the presentation of search results. And, it better integrates iCloud storage.

OSX Yosemite includes updates to Safari to make it "simpler and more powerful," said Brian Croll, vice president of software marketing.

The operating system's mail application was updated with MailDrop, which encrypts and routes large attachments that might be rejected by some mail servers through iCloud.

Apple's new IOS 8 operating system makes it easier to view an inbox while also writing an email. And, notifications on iOS 8 are interactive, allowing users to respond right from notification center.

A major addition to IOS 8 is HealthKit, a new health-tracking app for mobile devices that will track footsteps, heart rate and sleep activity for consolidating health related data.

The company will work in tandem with Nike Inc., a major player in fitness tracking, and the Mayo Clinic on the new feature, which will be included with the latest versions of Apple's mobile software.

“That information lives in silos,” said Federighi. “You can't get a single comprehensive picture.”

Federighi also introduced HomeKit, an interface that allows the phone to connect to Internet-enabled devices in the home, such as garage doors, doffee machines and alarm systems.

Cook, in opening the conference on Monday, said the iPhone maker has sold more than 800 million mobile devices. Some 130 million customers bought their first Apple mobile device in the past 12 months, he added.